Sittiing Spongebob Please Help Quick!

I need to make a SpongeBob cake where it looks like he is sitting...instead of a flat sheet cake. I have been through the galleries but they don't give much detail how it's done. Some say they use 9x13's cut in half or into 3rd's but don't really explain how to cut, stack, etc.

I did a cake like this a couple months ago by making four cakes using loaf pans and stacked them. I put two dowels rods through it. The bad thing was I stacked Spongebob on top of a sheet cake, so he wobbled whenever we moved the whole cake. About gave me a heart attack during delivery! You can see the image in my pictures.

I used square cakes stacked up with boards between the layers. I doweled the lower layers and ran a dowel through the middle of the whole thing. Then I iced in buttercream and added the fondant decorations. I can't remember if I used straight fondant or RKT for the arms and legs. Here's a link to the one I did:

I made a Sponge Bob a couple weeks ago, I was going to follow a tuturiol I found on line but my oven broke the week of the cake so I did sponge bob out of RKT, I had to bake and make the cake at the birthday girls house so I made sponge bob ahead of time and had him sit on top of a cake the birthday girl helped me make and decorate.